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de Vries F, Slizovskiy S, Tomić P, Krishna Kumar R, Garcia-Ruiz A, Zheng G, Portolés E, Ponomarenko LA, Geim AK, Watanabe K, Taniguchi T, Fal’ko V, Ensslin K, Ihn T, Rickhaus P. Kagome Quantum Oscillations in Graphene Superlattices. Nano Lett 2024; 24:601-606. [PMID: 38180909 PMCID: PMC10797620 DOI: 10.1021/acs.nanolett.3c03524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/17/2023] [Accepted: 12/19/2023] [Indexed: 01/07/2024]
Abstract
Electronic spectra of solids subjected to a magnetic field are often discussed in terms of Landau levels and Hofstadter-butterfly-style Brown-Zak minibands manifested by magneto-oscillations in two-dimensional electron systems. Here, we present the semiclassical precursors of these quantum magneto-oscillations which appear in graphene superlattices at low magnetic field near the Lifshitz transitions and persist at elevated temperatures. These oscillations originate from Aharonov-Bohm interference of electron waves following open trajectories that belong to a kagome-shaped network of paths characteristic for Lifshitz transitions in the moire superlattice minibands of twistronic graphenes.
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Affiliation(s)
| | - Sergey Slizovskiy
- National
Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom
- Department
of Physics & Astronomy, University of
Manchester, Manchester M13 9PL, United Kingdom
| | - Petar Tomić
- Laboratory
for Solid State Physics, ETH Zürich, Zürich CH-8093, Switzerland
| | - Roshan Krishna Kumar
- National
Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom
- Department
of Physics & Astronomy, University of
Manchester, Manchester M13 9PL, United Kingdom
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, Barcelona 08028, Spain
| | - Aitor Garcia-Ruiz
- National
Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom
- Department
of Physics & Astronomy, University of
Manchester, Manchester M13 9PL, United Kingdom
| | - Giulia Zheng
- Laboratory
for Solid State Physics, ETH Zürich, Zürich CH-8093, Switzerland
| | - Elías Portolés
- Laboratory
for Solid State Physics, ETH Zürich, Zürich CH-8093, Switzerland
| | | | - Andre K. Geim
- National
Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom
- Department
of Physics & Astronomy, University of
Manchester, Manchester M13 9PL, United Kingdom
| | - Kenji Watanabe
- National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Vladimir Fal’ko
- National
Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom
- Department
of Physics & Astronomy, University of
Manchester, Manchester M13 9PL, United Kingdom
- Henry
Royce
Institute for Advanced Materials, Manchester M13 9PL, United Kingdom
| | - Klaus Ensslin
- Laboratory
for Solid State Physics, ETH Zürich, Zürich CH-8093, Switzerland
| | - Thomas Ihn
- Laboratory
for Solid State Physics, ETH Zürich, Zürich CH-8093, Switzerland
| | - Peter Rickhaus
- Laboratory
for Solid State Physics, ETH Zürich, Zürich CH-8093, Switzerland
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2
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Seitsonen AP, Greber T. Growing sp 2 materials on transition metals: calculated atomic adsorption energies of hydrogen, boron, carbon, nitrogen, and oxygen atoms, C 2 and BN dimers, C 6 and (BN) 3 hexamers, graphene and h-BN with and without atomic vacancies. Nanoscale Adv 2023; 6:268-275. [PMID: 38125605 PMCID: PMC10729893 DOI: 10.1039/d3na00472d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/31/2023] [Indexed: 12/23/2023]
Abstract
The growth of graphene and hexagonal boron nitride on hot transition metal surfaces involves the adsorption of precursor molecules, and their dissociation and assembly into two-dimensional honeycomb lattices. In a recent account it was found that h-BN may be distilled on a rhodium metal surface, which yields higher quality h-BN [Cun et al., ACS Nano, 2020, 15, 1351]. In this context, we calculated in a systematic approach the adsorption energies and sites of hydrogen, boron, carbon, nitrogen, and oxygen atoms and from the site dependence the activation energy for diffusion. Existing computed values of the solvation energy into the bulk were compared to the present ones with our calculation scheme and found to be in good agreement. For the distinction of different systems we introduce the concepts of epiphilicity and epiphobicity. The adsorption energies and stabilities of the C2 and BN dimers, the C6 and (BN)3 ring-hexamers and the graphene and h-BN monolayers allow the prediction of the performance of different substrates in chemical vapor deposition (CVD) processes for the growth of graphene and h-BN. Finally, vacancy creation energies were calculated as a criterion for the stability of graphene and h-BN on metallic substrates.
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Affiliation(s)
| | - Thomas Greber
- Physik-Institut, Universität Zürich CH-8057 Zürich Switzerland +41 44635 5704 +4144 635 5744
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3
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Liu Y, Brinkhoff T, Berger M, Poehlein A, Voget S, Paoli L, Sunagawa S, Amann R, Simon M. Metagenome-assembled genomes reveal greatly expanded taxonomic and functional diversification of the abundant marine Roseobacter RCA cluster. Microbiome 2023; 11:265. [PMID: 38007474 PMCID: PMC10675870 DOI: 10.1186/s40168-023-01644-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/07/2023] [Indexed: 11/27/2023]
Abstract
BACKGROUND The RCA (Roseobacter clade affiliated) cluster belongs to the family Roseobacteracea and represents a major Roseobacter lineage in temperate to polar oceans. Despite its prevalence and abundance, only a few genomes and one described species, Planktomarina temperata, exist. To gain more insights into our limited understanding of this cluster and its taxonomic and functional diversity and biogeography, we screened metagenomic datasets from the global oceans and reconstructed metagenome-assembled genomes (MAG) affiliated to this cluster. RESULTS The total of 82 MAGs, plus five genomes of isolates, reveal an unexpected diversity and novel insights into the genomic features, the functional diversity, and greatly refined biogeographic patterns of the RCA cluster. This cluster is subdivided into three genera: Planktomarina, Pseudoplanktomarina, and the most deeply branching Candidatus Paraplanktomarina. Six of the eight Planktomarina species have larger genome sizes (2.44-3.12 Mbp) and higher G + C contents (46.36-53.70%) than the four Pseudoplanktomarina species (2.26-2.72 Mbp, 42.22-43.72 G + C%). Cand. Paraplanktomarina is represented only by one species with a genome size of 2.40 Mbp and a G + C content of 45.85%. Three novel species of the genera Planktomarina and Pseudoplanktomarina are validly described according to the SeqCode nomenclature for prokaryotic genomes. Aerobic anoxygenic photosynthesis (AAP) is encoded in three Planktomarina species. Unexpectedly, proteorhodopsin (PR) is encoded in the other Planktomarina and all Pseudoplanktomarina species, suggesting that this light-driven proton pump is the most important mode of acquiring complementary energy of the RCA cluster. The Pseudoplanktomarina species exhibit differences in functional traits compared to Planktomarina species and adaptations to more resource-limited conditions. An assessment of the global biogeography of the different species greatly expands the range of occurrence and shows that the different species exhibit distinct biogeographic patterns. They partially reflect the genomic features of the species. CONCLUSIONS Our detailed MAG-based analyses shed new light on the diversification, environmental adaptation, and global biogeography of a major lineage of pelagic bacteria. The taxonomic delineation and validation by the SeqCode nomenclature of prominent genera and species of the RCA cluster may be a promising way for a refined taxonomic identification of major prokaryotic lineages and sublineages in marine and other prokaryotic communities assessed by metagenomics approaches. Video Abstract.
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Affiliation(s)
- Yanting Liu
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Carl Von Ossietzky Str. 9-11, 26129, Oldenburg, Germany.
- Max Planck Institute for Marine Microbiology, Bremen, Germany.
- State Key Laboratory for Marine Environmental Science, Institute of Marine Microbes and Ecospheres, Xiamen University, Xiamen, People's Republic of China.
| | - Thorsten Brinkhoff
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Carl Von Ossietzky Str. 9-11, 26129, Oldenburg, Germany.
| | - Martine Berger
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Carl Von Ossietzky Str. 9-11, 26129, Oldenburg, Germany
| | - Anja Poehlein
- Department of Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Georg-August University Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany
| | - Sonja Voget
- Department of Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Georg-August University Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany
| | - Lucas Paoli
- Department of Biology, Institute of Microbiology and Swiss Institute of Bioinformatics, ETH Zürich, Zurich, Switzerland
| | - Shinichi Sunagawa
- Department of Biology, Institute of Microbiology and Swiss Institute of Bioinformatics, ETH Zürich, Zurich, Switzerland
| | - Rudolf Amann
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Meinhard Simon
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Carl Von Ossietzky Str. 9-11, 26129, Oldenburg, Germany.
- Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Ammerländer Heerstr. 231, 26129, Oldenburg, Germany.
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Ungerer JH, Sarmah D, Kononov A, Ridderbos J, Haller R, Cheung LY, Schönenberger C. Performance of high impedance resonators in dirty dielectric environments. EPJ Quantum Technol 2023; 10:41. [PMID: 37810533 PMCID: PMC10558395 DOI: 10.1140/epjqt/s40507-023-00199-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 09/27/2023] [Indexed: 10/10/2023]
Abstract
High-impedance resonators are a promising contender for realizing long-distance entangling gates between spin qubits. Often, the fabrication of spin qubits relies on the use of gate dielectrics which are detrimental to the quality of the resonator. Here, we investigate loss mechanisms of high-impedance NbTiN resonators in the vicinity of thermally grown SiO2 and Al2O3 fabricated by atomic layer deposition. We benchmark the resonator performance in elevated magnetic fields and at elevated temperatures and find that the internal quality factors are limited by the coupling between the resonator and two-level systems of the employed oxides. Nonetheless, the internal quality factors of high-impedance resonators exceed 103 in all investigated oxide configurations which implies that the dielectric configuration would not limit the performance of resonators integrated in a spin-qubit device. Because these oxides are commonly used for spin qubit device fabrication, our results allow for straightforward integration of high-impedance resonators into spin-based quantum processors. Hence, these experiments pave the way for large-scale, spin-based quantum computers.
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Affiliation(s)
- J. H. Ungerer
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - D. Sarmah
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - A. Kononov
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - J. Ridderbos
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
- Present Address: NanoElectronics Group, MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - R. Haller
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - L. Y. Cheung
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - C. Schönenberger
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
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5
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Morgan N, Dubrovskii VG, Stief AK, Dede D, Sanglé-Ferrière M, Rudra A, Piazza V, Fontcuberta i Morral A. From Layer-by-Layer Growth to Nanoridge Formation: Selective Area Epitaxy of GaAs by MOVPE. Cryst Growth Des 2023; 23:5083-5092. [PMID: 37426543 PMCID: PMC10326851 DOI: 10.1021/acs.cgd.3c00316] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/01/2023] [Indexed: 07/11/2023]
Abstract
Selective area epitaxy at the nanoscale enables fabrication of high-quality nanostructures in regular arrays with predefined geometry. Here, we investigate the growth mechanisms of GaAs nanoridges on GaAs (100) substrates in selective area trenches by metal-organic vapor-phase epitaxy (MOVPE). It is found that pre-growth annealing results in the formation of valley-like structures of GaAs with atomic terraces inside the trenches. MOVPE growth of GaAs nanoridges consists of three distinct stages. Filling the trench in the first stage exhibits a step-flow growth behavior. Once the structure grows above the mask surface, it enters the second stage of growth by forming {101} side facets as the (100) flat top facet progressively shrinks. In the third stage, the fully formed nanoridge begins to overgrow onto the mask with a significantly reduced growth rate. We develop a kinetic model that accurately describes the width-dependent evolution of the nanoridge morphology through all three stages. MOVPE growth of fully formed nanoridges takes only about 1 min, which is 60 times faster than in our set of molecular beam epitaxy (MBE) experiments reported recently, and with a more regular, triangular cross-sectional geometry defined solely by the {101} facets. In contrast to MBE, no material loss due to Ga adatom diffusion onto the mask surface is observed in MOVPE until the third stage of growth. These results are useful for the fabrication of GaAs nanoridges of different dimensions on the same substrate for various applications and can be extended to other material systems.
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Affiliation(s)
- Nicholas Morgan
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Vladimir G. Dubrovskii
- Faculty
of Physics, Saint Petersburg State University, Universitetskaya Embankment 13B, 199034 St. Petersburg, Russia
| | - Ann-Kristin Stief
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Didem Dede
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Marie Sanglé-Ferrière
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Alok Rudra
- Laboratory
of Semiconductor Materials, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Valerio Piazza
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Anna Fontcuberta i Morral
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Laboratory
of Semiconductor Materials, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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6
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Canepa G, Cattaneo AS, Schiavina M. General Relativity and the AKSZ Construction. Commun Math Phys 2021; 385:1571-1614. [PMID: 34720125 PMCID: PMC8549958 DOI: 10.1007/s00220-021-04127-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 05/25/2021] [Indexed: 06/13/2023]
Abstract
In this note the AKSZ construction is applied to the BFV description of the reduced phase space of the Einstein-Hilbert and of the Palatini-Cartan theories in every space-time dimension greater than two. In the former case one obtains a BV theory for the first-order formulation of Einstein-Hilbert theory, in the latter a BV theory for Palatini-Cartan theory with a partial implementation of the torsion-free condition already on the space of fields. All theories described here are BV versions of the same classical system on cylinders. The AKSZ implementations we present have the advantage of yielding a compatible BV-BFV description, which is the required starting point for a quantization in presence of a boundary.
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Affiliation(s)
- G. Canepa
- Institut für Mathematik, Universität Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - A. S. Cattaneo
- Institut für Mathematik, Universität Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - M. Schiavina
- Institute for Theoretical Physics, ETH Zurich, Wolfgang Pauli strasse 27, 8092 Zurich, Switzerland
- Department of Mathematics, ETH Zurich, Rämistrasse 101, 8092 Zurich, Switzerland
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7
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Faist P, Berta M, Brandao FGSL. Thermodynamic Implementations of Quantum Processes. Commun Math Phys 2021; 384:1709-1750. [PMID: 34776522 PMCID: PMC8550554 DOI: 10.1007/s00220-021-04107-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 04/28/2021] [Indexed: 06/13/2023]
Abstract
Recent understanding of the thermodynamics of small-scale systems have enabled the characterization of the thermodynamic requirements of implementing quantum processes for fixed input states. Here, we extend these results to construct optimal universal implementations of a given process, that is, implementations that are accurate for any possible input state even after many independent and identically distributed (i.i.d.) repetitions of the process. We find that the optimal work cost rate of such an implementation is given by the thermodynamic capacity of the process, which is a single-letter and additive quantity defined as the maximal difference in relative entropy to the thermal state between the input and the output of the channel. Beyond being a thermodynamic analogue of the reverse Shannon theorem for quantum channels, our results introduce a new notion of quantum typicality and present a thermodynamic application of convex-split methods.
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Affiliation(s)
- Philippe Faist
- Institute for Quantum Information and Matter, Caltech, Pasadena, CA 91125 USA
- Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland
- Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, 14195 Berlin, Germany
| | - Mario Berta
- Institute for Quantum Information and Matter, Caltech, Pasadena, CA 91125 USA
- Department of Computing, Imperial College London, London, SW7 2AZ UK
- AWS Center for Quantum Computing, Pasadena, CA 91125 USA
| | - Fernando G. S. L. Brandao
- Institute for Quantum Information and Matter, Caltech, Pasadena, CA 91125 USA
- AWS Center for Quantum Computing, Pasadena, CA 91125 USA
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8
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Jones AT, Scheller CP, Prance JR, Kalyoncu YB, Zumbühl DM, Haley RP. Progress in Cooling Nanoelectronic Devices to Ultra-Low Temperatures. J Low Temp Phys 2020; 201:772-802. [PMID: 33239828 PMCID: PMC7679351 DOI: 10.1007/s10909-020-02472-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/29/2020] [Indexed: 06/11/2023]
Abstract
Here we review recent progress in cooling micro-/nanoelectronic devices significantly below 10 mK. A number of groups worldwide are working to produce sub-millikelvin on-chip electron temperatures, motivated by the possibility of observing new physical effects and improving the performance of quantum technologies, sensors and metrological standards. The challenge is a longstanding one, with the lowest reported on-chip electron temperature having remained around 4 mK for more than 15 years. This is despite the fact that microkelvin temperatures have been accessible in bulk materials since the mid-twentieth century. In this review, we describe progress made in the last 5 years using new cooling techniques. Developments have been driven by improvements in the understanding of nanoscale physics, material properties and heat flow in electronic devices at ultralow temperatures and have involved collaboration between universities and institutes, physicists and engineers. We hope that this review will serve as a summary of the current state of the art and provide a roadmap for future developments. We focus on techniques that have shown, in experiment, the potential to reach sub-millikelvin electron temperatures. In particular, we focus on on-chip demagnetisation refrigeration. Multiple groups have used this technique to reach temperatures around 1 mK, with a current lowest temperature below 0.5 mK.
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Affiliation(s)
- A. T. Jones
- Department of Physics, Lancaster University, Lancaster, LA1 4YB UK
| | - C. P. Scheller
- Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - J. R. Prance
- Department of Physics, Lancaster University, Lancaster, LA1 4YB UK
| | - Y. B. Kalyoncu
- Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - D. M. Zumbühl
- Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - R. P. Haley
- Department of Physics, Lancaster University, Lancaster, LA1 4YB UK
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9
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Krylov DS, Schimmel S, Dubrovin V, Liu F, Nguyen TTN, Spree L, Chen C, Velkos G, Bulbucan C, Westerström R, Studniarek M, Dreiser J, Hess C, Büchner B, Avdoshenko SM, Popov AA. Substrate-Independent Magnetic Bistability in Monolayers of the Single-Molecule Magnet Dy 2 ScN@C 80 on Metals and Insulators. Angew Chem Int Ed Engl 2020; 59:5756-5764. [PMID: 31860759 PMCID: PMC7155138 DOI: 10.1002/anie.201913955] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 12/11/2019] [Indexed: 01/08/2023]
Abstract
Magnetic hysteresis is demonstrated for monolayers of the single-molecule magnet (SMM) Dy2 ScN@C80 deposited on Au(111), Ag(100), and MgO|Ag(100) surfaces by vacuum sublimation. The topography and electronic structure of Dy2 ScN@C80 adsorbed on Au(111) were studied by STM. X-ray magnetic CD studies show that the Dy2 ScN@C80 monolayers exhibit similarly broad magnetic hysteresis independent on the substrate used, but the orientation of the Dy2 ScN cluster depends strongly on the surface. DFT calculations show that the extent of the electronic interaction of the fullerene molecules with the surface is increasing dramatically from MgO to Au(111) and Ag(100). However, the charge redistribution at the fullerene-surface interface is fully absorbed by the carbon cage, leaving the state of the endohedral cluster intact. This Faraday cage effect of the fullerene preserves the magnetic bistability of fullerene-SMMs on conducting substrates and facilitates their application in molecular spintronics.
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Affiliation(s)
- Denis S. Krylov
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
- Center for Quantum NanoscienceInstitute for Basic Science (IBS)SeoulRepublic of Korea
| | - Sebastian Schimmel
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
| | - Vasilii Dubrovin
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
| | - Fupin Liu
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
| | - T. T. Nhung Nguyen
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
| | - Lukas Spree
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
| | - Chia‐Hsiang Chen
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
- Department of Medicinal and Applied ChemistryKaohsiung Medical UniversityKaohsiung807Taiwan
| | - Georgios Velkos
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
| | - Claudiu Bulbucan
- The division of synchrotron radiation researchLund University22100LundSweden
| | - Rasmus Westerström
- The division of synchrotron radiation researchLund University22100LundSweden
| | - Michał Studniarek
- Swiss Light SourcePaul Scherrer Institute5232Villigen PSISwitzerland
| | - Jan Dreiser
- Swiss Light SourcePaul Scherrer Institute5232Villigen PSISwitzerland
| | - Christian Hess
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
| | - Stanislav M. Avdoshenko
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
| | - Alexey A. Popov
- Leibniz Institute for Solid State and Materials ResearchHelmholtzstraße 2001069DresdenGermany
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10
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Spree L, Schlesier C, Kostanyan A, Westerström R, Greber T, Büchner B, Avdoshenko SM, Popov AA. Single-Molecule Magnets DyM 2 N@C 80 and Dy 2 MN@C 80 (M=Sc, Lu): The Impact of Diamagnetic Metals on Dy 3+ Magnetic Anisotropy, Dy⋅⋅⋅Dy Coupling, and Mixing of Molecular and Lattice Vibrations. Chemistry 2020; 26:2436-2449. [PMID: 31774196 PMCID: PMC7065109 DOI: 10.1002/chem.201904879] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Indexed: 01/11/2023]
Abstract
The substitution of scandium in fullerene single-molecule magnets (SMMs) DySc2 N@C80 and Dy2 ScN@C80 by lutetium has been studied to explore the influence of the diamagnetic metal on the SMM performance of dysprosium nitride clusterfullerenes. The use of lutetium led to an improved SMM performance of DyLu2 N@C80 , which shows a higher blocking temperature of magnetization (TB =9.5 K), longer relaxation times, and broader hysteresis than DySc2 N@C80 (TB =6.9 K). At the same time, Dy2 LuN@C80 was found to have a similar blocking temperature of magnetization to Dy2 ScN@C80 (TB =8 K), but substantially different interactions between the magnetic moments of the dysprosium ions in the Dy2 MN clusters. Surprisingly, although the intramolecular dipolar interactions in Dy2 LuN@C80 and Dy2 ScN@C80 are of similar strength, the exchange interactions in Dy2 LuN@C80 are close to zero. Analysis of the low-frequency molecular and lattice vibrations showed strong mixing of the lattice modes and endohedral cluster librations in k-space. This mixing simplifies the spin-lattice relaxation by conserving the momentum during the spin flip and helping to distribute the moment and energy further into the lattice.
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Affiliation(s)
- Lukas Spree
- Leibniz Institute for Solid State and Materials Research (IFW Dresden)01069DresdenGermany
| | - Christin Schlesier
- Leibniz Institute for Solid State and Materials Research (IFW Dresden)01069DresdenGermany
| | - Aram Kostanyan
- Physik-Institut der Universität ZürichWinterthurerstr. 1908057ZürichSwitzerland
| | - Rasmus Westerström
- Physik-Institut der Universität ZürichWinterthurerstr. 1908057ZürichSwitzerland
- The Division of Synchrotron Radiation ResearchLund University22100LundSweden
| | - Thomas Greber
- Physik-Institut der Universität ZürichWinterthurerstr. 1908057ZürichSwitzerland
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research (IFW Dresden)01069DresdenGermany
| | | | - Alexey A. Popov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden)01069DresdenGermany
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Rohner D, Thiel L, Müller B, Kasperczyk M, Kleiner R, Koelle D, Maletinsky P. Real-Space Probing of the Local Magnetic Response of Thin-Film Superconductors Using Single Spin Magnetometry. Sensors (Basel) 2018; 18:E3790. [PMID: 30404146 PMCID: PMC6263703 DOI: 10.3390/s18113790] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 11/16/2022]
Abstract
We report on direct, real-space imaging of the stray magnetic field above a micro-scale disc of a thin film of the high-temperature superconductor YBa₂Cu₃O7-δ (YBCO) using scanning single spin magnetometry. Our experiments yield a direct measurement of the sample's London penetration depth and allow for a quantitative reconstruction of the supercurrents flowing in the sample as a result of Meissner screening. These results show the potential of scanning single spin magnetometry for studies of the nanoscale magnetic properties of thin-film superconductors, which could be readily extended to elevated temperatures or magnetic fields.
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Affiliation(s)
- Dominik Rohner
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
| | - Lucas Thiel
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
| | - Benedikt Müller
- Physikalisches Institut and Center for Quantum Science (CQ) in LISA+, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany.
| | - Mark Kasperczyk
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
| | - Reinhold Kleiner
- Physikalisches Institut and Center for Quantum Science (CQ) in LISA+, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany.
| | - Dieter Koelle
- Physikalisches Institut and Center for Quantum Science (CQ) in LISA+, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany.
| | - Patrick Maletinsky
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
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12
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Wilts BD, Vey AJM, Briscoe AD, Stavenga DG. Longwing (Heliconius) butterflies combine a restricted set of pigmentary and structural coloration mechanisms. BMC Evol Biol 2017; 17:226. [PMID: 29162029 PMCID: PMC5699198 DOI: 10.1186/s12862-017-1073-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 11/15/2017] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Longwing butterflies, Heliconius sp., also called heliconians, are striking examples of diversity and mimicry in butterflies. Heliconians feature strongly colored patterns on their wings, arising from wing scales colored by pigments and/or nanostructures, which serve as an aposematic signal. RESULTS Here, we investigate the coloration mechanisms among several species of Heliconius by applying scanning electron microscopy, (micro)spectrophotometry, and imaging scatterometry. We identify seven kinds of colored scales within Heliconius whose coloration is derived from pigments, nanostructures or both. In yellow-, orange- and red-colored wing patches, both cover and ground scales contain wavelength-selective absorbing pigments, 3-OH-kynurenine, xanthommatin and/or dihydroxanthommatin. In blue wing patches, the cover scales are blue either due to interference of light in the thin-film lower lamina (e.g., H. doris) or in the multilayered lamellae in the scale ridges (so-called ridge reflectors, e.g., H. sara and H. erato); the underlying ground scales are black. In the white wing patches, both cover and ground scales are blue due to their thin-film lower lamina, but because they are stacked upon each other and at the wing substrate, a faint bluish to white color results. Lastly, green wing patches (H. doris) have cover scales with blue-reflecting thin films and short-wavelength absorbing 3-OH-kynurenine, together causing a green color. CONCLUSIONS The pigmentary and structural traits are discussed in relation to their phylogenetic distribution and the evolution of vision in this highly interesting clade of butterflies.
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Affiliation(s)
- Bodo D Wilts
- Computational Physics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, NL-9747AG, Groningen, The Netherlands.
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700, Fribourg, Switzerland.
| | - Aidan J M Vey
- Computational Physics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, NL-9747AG, Groningen, The Netherlands
| | - Adriana D Briscoe
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92697, USA
| | - Doekele G Stavenga
- Computational Physics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, NL-9747AG, Groningen, The Netherlands
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